Last Updated on 27 July 2019   |   Print Email
In this article, we discuss three different ways for reading input from the user in the command line environment (also known as the “console”). Each way is fairly easy to use and also has its own advantages and drawbacks.
1. Reading User's Input using BufferedReader class
By wrapping the System.in (standard input stream) in an InputStreamReader which is wrapped in a BufferedReader, we can read input from the user in the command line. Here’s an example:
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Enter your name: ");
String name = reader.readLine();
System.out.println("Your name is: " + name);
In the above example, the readLine() method reads a line of text from the command line.Advantages: The input is buffered for efficient reading.Drawbacks: The wrapping code is hard to remember.
2. Reading User's Input using Scanner class
The main purpose of the Scanner class (available since Java 1.5) is to parse primitive types and strings using regular expressions, however it is also can be used to read input from the user in the command line. Here’s an example:
Scanner scanner = new Scanner(System.in);
System.out.print("Enter your nationality: ");
String nationality = scanner.nextLine();
System.out.print("Enter your age: ");
int age = scanner.nextInt();
Advantages:
Convenient methods for parsing primitives (nextInt(), nextFloat(), …) from the tokenized input.
The Console class was introduced in Java 1.6, and it has been becoming a preferred way for reading user’s input from the command line. In addition, it can be used for reading password-like input without echoing the characters entered by the user; the format string syntax can also be used (like System.out.printf()). Here’s an example code snippet:
Nam Ha Minh is certified Java programmer (SCJP and SCWCD). He started programming with Java in the time of Java 1.4 and has been falling in love with Java since then. Make friend with him on Facebook and watch his Java videos you YouTube.